Method of treating chlorates for blasting purposes



Patented Feb. 28, 1933 PER OLOV BTbBKMAN, OF TAINIONKUSKI, ANDLEONID'IVANOFF, 0F A130, FINLAND, ASSEGll'OR-S T0 FINSKA ELEKTBOKEMISKAAKTIEEOLAGET, OE HELSINGFGBS,

FINLAND T/IETEOD OF TREATING OHLORATES FOB BLASTING PURPOSES No Drawing.Application filed November 10, 1930, Serial No. 4.9%,806, and in SwedenMay 8, 1928.

This invention relates to an improved method of treating chlorates forblasting purposes.

It is already known to use for blasting purposes oxidizing substances,such as for instance chlorates, and to mix them immediately before theuse with combustible substances, such as for instance combustibleliquids. The manufacture of such explosives as well as their transportand use is quite as safe as the manufacture and use of pure chlorate dueto the fact that the two ingredients of the explosive are transportedand stored separately. According to the known methods it was, however,not possible to produce a perfectly good explosive and espeoially it wastroublesome to bring together the ingredients of the explosive in thedesired proportions.

The chief object of this invention is to bring the chlorate into a formwhich is well suited for use in the manufacture of explosives consistingof chlorate as oxidizing agent and a combustible agent.

The invention consists, chiefly, in this that the chlorate with orwithout additions which do not make the mixture explosive per se isbrought to a finely divided or dusty and moist state and then compressedand dried under heating, thus cementing the chlorate grains together tosolid porous briquettes the porosity of which amounts at least to 10% byvolume. The desired porosity is obtained by suitably selecting thepressure used, the fineness of the chlorate, its natural or artificialpercentage of moisture and the quantity of other additions possiblyused. The chlorate used may consist of potassium chlorate, sodiumchlorate or any other chlorate or perchlorate hitherto used for blastingpurposes.

Before the chlorate is moulded into briquettes it is disintegrated tosuch a fineness that at least 90% of the powder passes through a sievewith 80 to 100 meshes pr. cm. Immediately before the use of thebriquettes for blasting purposes they are impregnated with combustiblesubstances in the form of liquids, solutions or melts until they arepartly or wholly saturated therewith.

The briquettes are, preferably, coated at the moulding or afterwardswith one or more envelopes adhering to the surface as a protecting coverduring transport and storing. The briquettes are, preferably, madetubular in such manner that they are provided with one or more channelsfor the purpose of facilitating the absorption of the combustiblesubstances and the introduction of a detonator. v

The impregnation of the briquettes is, prefrably, carried out in suchmanner that the briquettes are charged into a vessel, vat or the like,containing the combustible liquid which then in a few minutes isabsorbed by the briquettes. The maximum quantity of liquid absorbed isdetermined. beforehand by t 1e porosity of the briquettes but it may beregulatedat will by dipping the briquettes into the liquid only for amore or less short period. In such manner also the explosive power isregulated. Only after said impregnation which is effected in a fewminutes the briquette is a finished explosive which may be brought toexplode only by a powerful detonator (No. 6 or No. 8). The briquettesare in other respects quite safe, i. e. insensible to heat and tomechanical stress. If they for instance are held in a flame before theimpregnation they only melt as a stick of sealing wax and in impregnatedstate they burn without exploding. The risk at the handling of theexplosive is thus prac tically limited to the moment of charging or themoment of explosion.

As impregnating liquid any combustible liquid or solution may be used,as for instance petroleum and other liquid hydrocarbons, benzol,nitrobenzol, creosote oil, syrup, solutions of resin in alcohol, etc.Also combustible solid or half-solid'substances may be used if they inmolten state can be absorbed by the briquettes. Substances of the latterkind are for instance paraflin and other solid or semi-solidhydrocarbons and they may be used especially for the manufacture ofexplosives for blasting in water or in watery borings. By a suitablechoice of liquid and the quantity thereof the explosive may be suited todifferent purposes and for obtaining the most suitable blasting efl'ect.The explosive may thus be obtained either with properties like those ofblack gunpowder with its slow combustion or like that of dynamite withits rapid decomposition. The chlorate briquettes according to theinvention may, therefore, be regarded as a universal explosive.

In order to obtain briquettes of a good and uniform quality it issuitable to reduce the internal friction of the mass and thus increaseits plasticity. This may be done by adding substances such as an aqueousextract of peat, oils, gelatinous precipitates, tannin, graphite,kieselguhr etc. to the mass before or during its moulding to briquettes.By the addition of substances which at the drying of the briquettesshrink, for instance by loss of gases or water, or are gasified, forinstance 0, volatile substances such as ammonium carbonate and the like,the briquettes can obtain the desired porosit The detonation speed maybe increased by the addition to the mass before or during its mouldingof substances which at the use of the briquettes catalyticallyaccelerate the decomposition of the chlorate or increase the combustionand explosion temperature. Such catalytically acting substances are forinstance com ounds of iron co er cobalt nickel, chromium. and manganese,graphite, cyanides and sulphocy'anides etc. while carbides, certainmetal powders such as powder of aluminium, magnesium, silicon or siliconmetals etc. may be used as energy delivering means. It is, however, tobe noted that said additions should be used in such quantities only thatthe dried and unimpregnated briquettes maintain the desired porosity anddo not become explosive per se. A suitable manner of incorporating suchadditional substances in the briquettes is to add them to the powderedchlorate-as suspensions, emulsions, colloidal or moleculardispersoidalsolutions or to precipitate them in the chlorate powder during themixing operation. 7

Another manner of introducing for in stance the catalytically actingsubstances or substances having a high caloric value is to suspend suchsubstances colloidally or in other manner in the combustible liquids,solutions or melts with which the briquettes are to be impregnated.

The explosive powerof the briquettes may be regulated not only by thenature and the quantity of impregnating liquid used but also by thechoice of dctonatingmeans and its quantity.

What we claim is:

1. Method of treating chlorates for blasting purposes, which comprisesmixing finely disintegrated chlorate and water to form a plastic mass,mouldine said mass into blocks, drying said blocks until the chloratedissolved crystallizes out. and cements together ing purposes,whichcomprises mixing finely disintegrated chlorate and water to forma Iplastic mass, moulding said mass into blocks while applying pressure tocompress the mass, drying said blocks untll the chlorate dissolvedcrystallizes out and cements togather the chlorate powder to porousbriquettes having capillarity and adapted to be impregnated with acombustible liquid, the

quantity of water and the pressure used beso chosen that the pore volumeof the finished porous briquette amounts to at least- 10% ofthe totalvolumeof the briquette.

3. Method of treating chlorates for blasting purposes, which comprisesmixing finely disintegrated chlorate, water and a substance whichshrinks by drying, to form, a plastic mass, moulding said mass intoblocks, drysaid blocks until the chlorate dissolved crystallizes out andcement-s together the chic-H rate powder to porous briquettes adapted tobe impregnated with a combustibleliquid, the quantity of water being sorelated to the other ingredients of the plastic mass that the porevolume of the finished porous briquette amounts to at least 10% of thetotal Volume of the briquette.

4. Method of treating chlorates for blasting purposes, which comprisesmixing finely disintegrated chlorate, water and a solid voatilesubstance to form a plastic mass, moulding said mass into blocks,heating said blocks to expel the water and the volatile substance andtocement together the chlorate powder to porous briquettes adapted to beimpregnated with a combustible liquid, the quantities of water and ofthe volatile substance being so related to the chlorate that the poreVolume of the finished porous briquette amounts to at least 10% of thetotal Volume of the briquette.

In testimony whereof we have signed our names.

PER oLov BJonKMAN. LEONID IVANOFF.

